Short answer: a standard 12×12 bedroom needs 2 gallons of paint for two coats on the walls. Add 1 gallon if you are also painting the ceiling, for 3 gallons total. A small 10×10 bedroom also needs 2 gallons, while a large master bedroom needs 3 gallons for the walls alone.
How the bedroom paint calculation works
A 12×12 bedroom with 8-foot ceilings has 48 feet of wall perimeter (12 + 12 + 12 + 12). Multiply by the 8-foot height and you get 384 square feet of wall area. Subtract about 36 square feet for one door and one window and you have about 348 square feet of paintable wall. One gallon of paint covers about 350 square feet per coat, so two coats need about 696 square feet of coverage — 696 divided by 350 is 1.99 gallons, which rounds to 2 gallons to buy.
Paint needed by bedroom size
| Room size | Paintable wall area (2 coats) | Gallons needed | Buy this: |
|---|---|---|---|
| 10×10 bedroom | 568 sq ft | 1.62 gallons | 2 gallons |
| 12×12 bedroom | 696 sq ft | 1.99 gallons | 2 gallons + 1 quart for touch-ups |
| 10×12 bedroom | 632 sq ft | 1.81 gallons | 2 gallons |
| 14×18 master bedroom | 952 sq ft | 2.72 gallons | 3 gallons |
Assumes 8-foot ceilings, two coats, one door and one window; a room with two windows needs about 2.25 gallons — see the full 12×12 breakdown.
These figures assume 8-foot ceilings, two coats, and one gallon covering 350 square feet per coat. Textured walls, dark-to-light colour changes, or 9-foot ceilings can push you to the next gallon, so buying one extra quart for touch-ups is cheap insurance.
What about the ceiling?
A 12×12 ceiling is 144 square feet. Two coats need 288 square feet of coverage, which is 0.82 gallons — buy 1 gallon of ceiling paint. Ceiling paint is sold separately from wall paint, so do not count wall gallons toward the ceiling.
Frequently asked questions
Is 1 gallon enough paint for a bedroom?
No, not for two coats. One gallon covers about 350 square feet once, and a 12×12 bedroom needs about 696 square feet of coverage for two coats. One gallon is only enough for a single coat, or for one accent wall.
How much paint do I need for a bedroom with 9-foot ceilings?
Taller walls add about 12 percent more area. A 12×12 bedroom with 9-foot ceilings has about 432 square feet of wall area before doors and windows, and needs about 2.25 gallons for two coats — buy 2 gallons plus 1 quart, or 3 gallons to be safe.
Does primer count as a coat?
No. Primer is a separate base layer. If you are painting over a dark colour or new drywall, budget 1 extra gallon of primer for a standard bedroom, on top of the wall paint above.
Planning the whole room? Use the free paint calculator at free paint calculator to enter your exact room size and get your paint total before you buy.